What is the Maximum Contaminant Level (MCL) for nitrate?

The Maximum Contaminant Level (MCL) for nitrate is established at 10 milligrams per liter (mg/L) as nitrogen. This limit is put in place to protect public health, as elevated levels of nitrate in drinking water can pose serious health risks, particularly to infants and pregnant women. High nitrate concentrations can lead to a condition known as methemoglobinemia, or "blue baby syndrome," which affects the ability of blood to carry oxygen.

Setting the MCL at 10 mg/L helps ensure that drinking water remains safe and protects vulnerable groups from potential health hazards associated with excessive nitrate exposure. This regulation reflects extensive research and monitoring to identify a threshold that balances health safety with practicality for water treatment facilities.